Method of fabricating inkjet printhead with projections patterned across nozzle plate
View Patent ↗A method of fabricating an inkjet printhead. The method includes the steps of: (a) forming a plurality of MEMS ink ejection assemblies on an ink-ejection surface of a silicon substrate, each ink ejection assembly being sealed with roof material spanning across the ink ejection assemblies to define a nozzle plate; (b) etching partially into the roof material to form simultaneously a respective nozzle rim for each ink ejection assembly and a plurality of projections patterned across the nozzle plate between nozzle rims; and (c) etching through the roof material to form a respective nozzle aperture for each ink ejection assembly. The projections patterned across the nozzle plate between nozzle rims are useful for reducing stiction between particulates and the nozzle plate.
1. A method of fabricating an inkjet printhead, said method comprising the steps of:
(a) forming a plurality of MEMS ink ejection assemblies on an ink-ejection surface of a substrate, each ink ejection assembly being sealed with roof material, said roof material spanning across the ink ejection assemblies to define a nozzle plate;
(b) etching partially into said roof material to form simultaneously a respective nozzle rim for each ink ejection assembly and a plurality of projections patterned across said nozzle plate between nozzle rims; and
(c) etching through said roof material to form a respective nozzle aperture for each ink ejection assembly, thereby forming said inkjet printhead having said projections patterned across said nozzle plate.
2. The method of claim 1 , wherein each nozzle rim comprises at least one rim projection around a perimeter of each nozzle aperture.
3. The method of claim 2 , wherein each nozzle rim comprises a plurality of coaxial rim projections around a perimeter of each nozzle aperture.
4. The method of claim 2 , wherein said at least one rim projection projects at least 1 micron from said nozzle plate.
5. The method of claim 1 , wherein each of said projections patterned across said nozzle plate is a columnar projection.
6. The method of claim 5 , wherein each columnar projection projects at least 1 micron from said nozzle plate.
7. The method of claim 5 , wherein each columnar projection is spaced apart from an adjacent columnar projection by less than 2 microns.
8. The method of claim 1 , wherein each of said projections patterned across said nozzle plate comprises an elongate wall projection.
9. The method of claim 8 , wherein each wall projection projects at least 1 micron from said nozzle plate.
10. The method of claim 8 , wherein said wall projections are positioned for minimizing color-mixing of inks on said nozzle plate.
11. The method of claim 10 , wherein said wall projections extend along said nozzle plate parallel with rows of nozzles, each nozzle in a row ejecting the same colored ink.
12. The method of claim 1 , wherein the positions of said nozzle rims and each of said projections patterned across said nozzle plate are defined by photolithographic masking.
13. The method of claim 1 , wherein at least half of the surface area of said nozzle plate is patterned with said projections.
14. The method of claim 1 , wherein said nozzle plate is spaced apart from said substrate.
15. The method of claim 1 , wherein said nozzle plate is comprised of silicon nitride, silicon oxide, silicon oxynitride or aluminium nitride.
16. The method of claim 1 , wherein each ink ejection assembly is sealed by CVD or PECVD deposition of said roof material in step (a).
17. The method of claim 16 , wherein said roof material is deposited onto a sacrificial scaffold.
18. The method of claim 17 , wherein said sacrificial scaffold comprises photoresist.
19. The method of claim 18 , further comprising the step of:
removing said photoresist in an oxidizing plasma.